Securing the circular economy

One of the world’s biggest biogas plants when it was commissioned in 2009, the 13-hectare biogas park in Könnern, Saxony-Anhalt, Germany, was built by WELtec BioPower. Through an innovative treatment process, biogas produced at the plant is fed directly into the natural gas grid. Annual output is estimated to provide enough energy to heat about 10,000 homes.
At the heart of the process are 16 huge digesters. Each digester tank is 6.30 meters tall and 25 meters in diameter.

Because byproducts of the biogas production process include highly corrosive components like sulfur and ammonia, material used in the tanks (and equipment within those tanks) must be corrosion resistant. If corrosion occurs, damage to equipment is inevitable – and that is a particular problem, as restarting a digester after a breakdown is a long and delicate operation.

The cost-effective solution

In building the digester tanks themselves, cold-worked 2H surface allowed use of thinner steel with no loss of either strength or stability.
Because stainless steel is both thin and easy to work with, use of stainless steel in tank construction reduced construction time and logistics costs. And because it is corrosion resistant, there is less need for maintenance. In considering lifecycle costs, that translates into significant cost savings.

Improving reliability and efficiency

Biogas plants put stainless steel to work in multiple ways with optimal grades used in different parts of the application.

Corrosion resistance remains essential in a process marked by high temperatures, but the fully recyclable material’s other properties are equally important. Excellent formability and gas and water tightness eliminate leakage concerns.
And, because stainless steel’s surface is extremely smooth, aggressive substances are unable to attack it. Corrosion is nipped in the bud, an important factor in longevity. In short, stainless steel improves the reliability and efficiency of biogas plants.

Case facts

Challenge

The unique features of biogas production – organic waste and high temperatures – create a hostile environment for most materials.

Solution

Stainless steel is one of few materials that can withstand the aggressive gases and high temperatures common to biogas production. It is both corrosion resistant and keeps life-cycle costs down.

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About Outokumpu

Outokumpu is the global leader in stainless steel. Our customers use it to create civilization’s basic structures and its most famous landmarks. Stainless steel is sustainable, durable and designed to last forever.

We aim to be the best value creator in stainless by 2020, through our competitive edge of customer orientation and efficiency. The foundation of our business is our ability to tailor stainless steel into any form and for almost any purpose.

Outokumpu employs 10,000 professionals in more than 30 countries, with headquarters in Helsinki, Finland and shares listed in Nasdaq Helsinki.

Recycling maximized

Stainless steel is 100% recyclable. It is the most recycled material in the world, and its quality is preserved in the process.

Our stainless steel contains the highest proportion of recycled content on the market, and we keep pushing this further to conserve virgin raw materials. Increasing the share of recycled material is the single most effective measure to reduce our environmental impact.

Using Outokumpu’s stainless steel decreases our customer's own carbon footprint and that of their customers.